JPH076490Y2 - Electromagnetic flow meter - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application This invention relates to an electromagnetic flow meter.

(B) Conventional Technique FIGS. 4 and 5 are sectional views showing a conventional electromagnetic flowmeter.

This electromagnetic flowmeter comprises a non-magnetic measuring tube 1 provided with a lining layer 12 on its inner peripheral surface, and a magnetic field generating means provided outside the measuring tube 1 for generating a magnetic field orthogonal to the tube axis of the measuring tube 1. (A magnetic field generating portion formed by winding the coil 3 around the core 2),
On the inner wall of the measuring tube 1, a pair of electrodes 4 and 4a arranged to face each other orthogonally to the tube axis and the magnetic field of the measuring tube 1, one end to the electrode 4 (4a), and the other end to the terminal of the circuit section 7 And a lead wire 41 connected to the portion 71, and these components are covered with a cover 8 having a shield plate portion 81 on the inner surface.

When the fluid to be measured flows inside the measuring tube 1, a voltage is generated between the electrodes 4 and 4a corresponding to this flow velocity. By extracting this voltage with the lead wire 41, the flow rate of the fluid to be measured is measured.

(C) Problem to be Solved by the Invention The magnetic field generating means of the electromagnetic flowmeter is arranged on the outer circumference of the measuring tube 1 and between the flange portions 11, 11 at both ends, as shown in FIG. That is, the core 2 around which the exciting coil 3 is wound is provided in the upper peripheral portion and the lower peripheral portion of the measuring tube 1 so as to face each other. The exciting coil 3 is directly wound around the outer peripheral surface of the core 2.

In recent years, miniaturization of electromagnetic flowmeters, especially tube axis length (face-to-face distance)
A short measuring tube is required. However, in the conventional structure in which the coil is wound around the outer peripheral surface of the core, if the measuring tube is shortened, the width of the core and the coil (length in the tube axis direction)
Becomes shorter. This means that the magnetic field generation area in the tube is reduced, the magnetic flux density is reduced, and the electromotive force generated in the electrodes is reduced, resulting in poor measurement sensitivity. By the way, it is considered that a sufficient magnetic field generation region can be secured by increasing the number of coil turns. However, if the number of coil turns is increased with respect to a core having a short width, the coil as a whole becomes thicker, which is against the demand for size reduction. On the other hand, it is possible to secure a sufficient magnetic field region by increasing the exciting current. In other words, increasing the flowing current solves the problem of magnetic flux density reduction,
The power consumption increases accordingly, which is not preferable.

As a result, the conventional structure in which the coil is simply wound around the outer peripheral surface of the core cannot meet the demand for downsizing the electromagnetic flowmeter.

It is an object of the present invention to solve the above problems, to provide an electromagnetic flow meter that can be used for convenience, can accurately measure a flow rate, and can be downsized.

(D) Means and Actions for Solving the Problem In order to achieve this object, the electromagnetic flowmeter of the present invention has the following configuration.

The electromagnetic flowmeter is a non-magnetic measuring tube through which the fluid to be measured flows.
A magnetic field generating means which is provided outside the measuring tube and generates a magnetic field orthogonal to the tube axis of the measuring tube, and an inner wall of the measuring tube, which are arranged to face each other in a direction orthogonal to the tube axis and the magnetic field of the measuring tube. An electromagnetic flowmeter comprising at least a pair of electrodes, wherein the magnetic field generating means forms a recess inwardly of a predetermined depth in the peripheral surface of the core, and an exciting coil is wound around the recess. It is characterized by being deployed.

In the electromagnetic flowmeter having such a configuration, cores each having a coil wound are provided on the upper and lower peripheral portions of the measuring pipe having flange portions at both ends. This core is
It has a curved shape corresponding to the curvature of the measuring tube, and a concave portion is formed around the peripheral surface. An exciting coil is wound around the recess. Further, the width of the core (the length in the tube axis direction) is set to be the same as that of the conventional general core, and a sufficient magnetic field range is secured. By deploying the coil in the recess,
Even if the number of coil turns is the same as in the conventional case, the width of the coil (the length in the tube axis direction) becomes shorter than the conventional coil width by the depth of the recess. Therefore, the distance between the flanges (face-to-face distance) of the measuring pipe can be set short, and the electromagnetic flowmeter can be downsized.

(E) Embodiment FIG. 1 and FIG. 2 are sectional views showing a specific embodiment of the electromagnetic flowmeter according to the present invention.

As is well known, the electromagnetic flow meter is provided with a non-magnetic measuring tube 1 having a lining layer (an insulating layer made of Teflon, neoprene rubber, polyurethane, etc.) 12 on its inner peripheral surface, and a measuring tube 1 provided outside the measuring tube 1. A magnetic field generating means (a magnetic field generating part formed by winding the coil 3 around the core 2) for generating a magnetic field orthogonal to the tube axis of the tube 1, and an inner wall of the measuring tube 1 with respect to the tube axis and the magnetic field of the measuring tube 1. A pair of electrodes 4 arranged to face each other orthogonally,
4a and a lead wire (flexible cable) 41 having one end connected to the electrode 4 (4a) and the other end connected to the circuit terminal (terminal part) 71 of the circuit part 7, and these components are shielded on the inner surface. It is covered with a cover 8 having a portion 81.

The magnetic field generating means (consisting of the core 2 and the coil 3 wound around the outer peripheral surface of the core 2) is provided between the flange portions 11 at both ends of the measuring pipe 1, and the upper peripheral portion of the measuring pipe 1 and the pipe. In the lower part,
Each is deployed.

The feature of this invention resides in that a concave portion 21 is formed around the peripheral surface of the core 2 and the coil 3 is wound around the concave portion 21.

The core 2 has a curved shape (saddle shape) corresponding to the curvature of the measuring tube 1.
Thus, a concave portion 21 having a constant depth is formed on the peripheral surface. In the embodiment, as shown in FIG. 3, the core 2 is vertically divided into two parts at the center of thickness, and the core halves 22a and 2b are paired. Then, cutouts 21a, 21
b. When the half bodies 2a, 2b are brought into contact with each other, the recesses 21 are set by the notches 21a, 21b. Further, the core 2 is provided with engaging portions and engaging receiving portions on the contact surface portions of the upper and lower halves 2a and 2b so as to be detachable (not shown).

The exciting coil 3 is wound around the recess 21. The exciting coil 3 is similar to the conventional one, and the number of turns is also set similarly.

In the electromagnetic flowmeter having such a configuration, by setting the width of the core 2 (the length in the tube axis direction) to be the same as the width of the conventional core, a sufficient magnetic field range can be secured. There is. By disposing the coil 3 around the recessed portion 21, even if the number of turns of the coil 3 is the same as the conventional one, the recessed portion 21
The width of the coil 3 (the length in the tube axis direction) becomes smaller than the conventional coil width by the depth. Therefore, that much measurement tube 1
The pipe axis length (the length between both flange portions 11) of can be shortened, and the electromagnetic flowmeter can be miniaturized without reducing the magnetic field generation region.

In addition, the core 2 can separate the pair of upper and lower halves 2a and 2b. Therefore, when the coil 3 is mounted, the coil 3 is preliminarily wound by a predetermined mold and molded, and the separated cores (upper and lower halves 2a, 2b) 2 are mounted on the molded coil 3 (third part). See figure). As a result, the work of attaching the coil 3 and the core 2 is further simplified. Further, when a part of the core 2 around which the coil 3 is wound is damaged, the half 2a (2b) on the damaged side of the coil 3 can be removed and replaced.

(F) Effect of the device In this device, as described above, since the concave portion is formed on the peripheral surface of the core and the coil is wound around the concave portion, the width of the core (length in the axial direction of the pipe) Is set in the same manner as the conventional core width to secure a sufficient magnetic field range, and by winding the coil around the recess, the coil width (length in the axial direction of the tube) is increased by the depth of the recess. Can be made shorter than the conventional coil width. Therefore, the tube axial length (face-to-face distance) of the measuring tube can be set short, and the electromagnetic flowmeter can be downsized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an electromagnetic flowmeter of the embodiment cut in parallel with a pipe axis direction, and FIG. 2 is a cross-sectional view taken in a direction orthogonal to the pipe axis of the electromagnetic flowmeter of the embodiment, FIG. Is an explanatory view showing the relationship between the core and the coil of the embodiment electromagnetic flowmeter, and FIG.
FIG. 5 is a cross-sectional view showing a conventional electromagnetic flow meter taken along the tube axis, and FIG. 5 is a cross-sectional view taken along the direction perpendicular to the tube axis of the conventional electromagnetic flow meter. 1: Measuring tube, 2: Core, 3: Coil, 4 ・ 4a: Electrode, 21: Recessed part.

Claims (1)

[Scope of utility model registration request] 1. A non-magnetic measuring tube through which a fluid to be measured flows, magnetic field generating means provided outside the measuring tube for generating a magnetic field orthogonal to the tube axis of the measuring tube, and an inner wall of the measuring tube. An electromagnetic flowmeter comprising at least a pair of electrodes arranged to face each other in a direction orthogonal to the tube axis of the measuring tube and the magnetic field, wherein the magnetic field generating means is a concave portion that is recessed inward at a predetermined depth on the peripheral surface of the core. The electromagnetic flowmeter is characterized in that an exciting coil is wound around the recessed portion to form one round.